Apparatus for heat treatment by means of alpha bath of molten metal



Feb. 9,1926. 1,572,779

A. MCD. DUCKHAM APPARATUS FOR HEAT TREATMENT BY MEANS OF A BATH OF'MOLTEN METAL Filed June 20, 1923 Il. 0 gy Pam-med` Feb. 9, 192e.

UNITED STATES PATENT OFFICE.

ARTHUR-MUDOUGALL DUCKHAM, 0F LONDON, ENGLAND, ASSIGNOR T0 THERMALINDUSTRIAL .AND CHEMICAL (T. I. C.) RESEARCH COMPANY LIMITED, 0F LON-DoN, ENGLAND.

LAPPARATUS FOB HEAT TREATMENT BY MEANS OF A BATH OF MOLTEN METAL.

Application led June 20, 1923. Serial No. 646,616.

To all whom it may concern.'

Be it known that I, ARTHUR MCDOUGALL DUCKHAM, a subject of the King ofGreat Britain, residing in London, England, have invented certain newand useful Improvements in Apparatus for Heat Treatment by Means of aBath of Molten Metal, of which the `following is a specification. v

In British Patent No. 14,617 of 1895 to McEuen there is disclosed anapparatus for causing material to travel through a bath of molten metalwhile submerged in the metal, which apparatus consists of an endlesschain or band travelling around drums within a closed vessel containingthe molten metal; the upper run of the chain travels at some distanceabove the surface of the metal and the lower travels beneath the surfaceof the metal. The chain carries at short distances projecting transversearms and between these the material under treatment is charged on to thechain from a hopper at one end of the vessel so that the material h isconveyed to the other end where it is car- 2 ried over the drum at thisend and is returned beneath the surface of the molten metal.

The considerable heat capacity of the chain operates adversely in suchan `ap a.- ratus. The upper run is cooled by radiation and by thematerial charged, particularly if the material is moist, and on becomingthe lower run is apt to freeze the molten metal in contact with it; thusthe material delivered on to the surface of the metal from the lower runcarries metal with it and the pivots of the chain become bound by themetal, greatly increasing the friction and even stopping the travel.Furthermore much of the eat imparted to the chain is lost to the bathwith bad economy.

The present invention in large degree obviates these objections bykeeping the lower run or stretch of the chain clear of the molten metal.To the same end, metal plates which are relatively thin, as comparedwith the arms disclosed in said British patent, and, by reason of thefact that 4they absorb comparatively little heat, do not materiallychill the molten metal, may be employed.

To reduce still further the mass of metal constituting the conveyor, thethin plates may be bent at right angles so that between the parts whichproject at right angles to the chain thereV are formed platforms onwhich the material to be treated rests. In this manner the chain can bereduced in width to that necessary for the strain which it has to bear,or there may be more still narrower chains.

To avoidsagging of the upper run or stretch of the chain or chains andto take the upward thrust on the lower run or stretch when the moltenmetal is of higher specic gravity than the metal plates, the latter maybe supported at their ends on ledges below them on the inner surfaces ofthe walls of the vessel during their travel with the upper run andyagainst like ledges above them during their travel with the lower run..

A construction according to the invention is shown in the accompanyingdrawings.l

Fig. 1 is a longitudinal section througha bath of molten lead and afurnace for heating the lead, the bath containing a conve or aving thefeatures of the invention; ig.

scale, on line 2-2 of Fig. 1.

` The bath a, set in a furnace b and having a gas tight cover c, ischarged' with liquid lead to the level d. The lshafts Z carry each twosprocket wheels e and on each pair of these wheels runs an endless chainf. The two chains carry a number of plates g of sheet iron as thin as isconstructionally permissible, which are bent at right angles, thehorizontal limbs being rivetted to the links of the chains. Angle ironsh, z' bolted to the sides of the bath support the ends of these platesin the manner already indicated.

It will be seen that the diameter of the sprocket wheels is such thatthe lower runs or stretches of the chains are just above the surface ofthe molten lead while the horizontal limbs of the plates are just on thesurface.

Each plate with that next it constitutes a bucket to receive material asit passes beneath the charging hopper 7c. One of the shafts Z beingdriven in the direction indicated by the arrow, the charged buckets areconveyed to the other end of the bath where they enter the molten met-a1carrying with them the material, which has been pre-heated and driedduring its travel on the upper run. 'The material thus travels throughthe lead and at the charging end of the bath substituted two or 1s across section, drawn to anA enlarged is delivered on-4 to the surface ofthe molten plates E, they' may be suitably perforated.

' The be treated in such an apparatus as here described are known. As anexample ofsuch material shale may be mentioned;

Having thus described the nature of my said invention and the best meansI know of carrying the same into practical effect, I claim 1. Apparatusof the character described,

Acomprising a chamber to contain molten metal, a chain travellingthrough said chamber above and in close proximity to the normal level ofthe metal in saidchamber, and

transverse plates projecting from the chain and dipping below the saidlevel.

2. Apparatus of the character described, comprising a chamberv tocontain molten metal, an endless travelling chain lying above the normallevel ofthe metal contained in said chamber and having a stretch whichis in close proximity to the said level, and transverse-plates attachedto and projecting from the chain, and extending below the said levelwhen they are positioned on the said stretch.

v 3. Apparatusof the character described, comprising 'a chamber tocontain molten metal, horizontal shafts mounted in said chamber,sprockets on said shafts situated above the normal level of the metal,an endless chain travellingaround said sprockets with its lower runabove and in close proximity to the said level, a plurality oftransverse plates projecting from said chain and dipping beneath thenormal level of the metal when positioned on the lower run of the chain,means for rotating one ofthe said shafts, means for feeding the materialto be treated into the chamber, and means chamber.

, 4:. Apparatus of the character described, comprising a chamber tocontain molten metal, horizontal 'shafts mounted in said for removingthe treated material from the chamber, sprockets on said shafts situatedabove the normal level of the metal contained in said chamber, anendless chain travelling around said sprockets. with its inds ofmaterial which may usefullyV lower run above and in close roximity tovthe said level, a plurality o thin metal ing its other limb projectingperpendicularl from the chain and dippin beneath sai level whenpositioned on the Iower run of the chain, means for rotatingA one of thesaid shafts, means for feeding material to be treated between thepro'ecting limbs of the plates when positione run of the chain, andmeans for removing the treated material from the chamber.

5. Apparatus of the'character described, comprising a chamber to containmolten metal, horizontal shafts mounted in said chamber, sprpckets'onsaid shafts situated above the normal level of the metal contained insaid chamber, an endless chain travelling around said sprockets with itslower run above and yin close proximity to thesaid level, a pluralit oftransverse plates projecting from sai chain and dipping beneath saidlevel when positioned on the lower run of` the chain, ledges on thesides of 'said chamber supporting said plates during their travelbetween the sprockets,

means for rotating one'of the said shafts,y

means for feeding material to be treated into the chamber and means forremoving the treated material from the chamber.

6. Apparatus of the character described, comprising a chamber/to containmolten metal, horizontal shafts mounted in said chamber, sprockets onsaid shafts situated abovejtlie normal level of the metal in saidchamber, an endless chain travelling around said sprockets with itslower run above and in close proximity to the said level, a plurality ofthin* metal plates 'bent at right angles and leach havingvone limbsecured to said chain and its other limb projecting perpendicularly fromthe chain and dipping beneath such level when positioned on the- 'ARTHURMCDOUGALL nUoKHiM.

on the upper

